Combustion apparatus using compressed air



Sept. 2, 1952 D. ARONSON COMBUSTION APPARATUS USING COMPRESSED AIR 2 SHEETS-SHEET 1 Filed March 14, 1950 INVENTOR. 0/1 1 10 Aka/v50.

Sept. 2, v1952 D. ARONSON 2,509,040

COMBUSTION APPARATUS USING COMPRESSED AIR Filed March 14, 1950 2 SHEETS-SHEET 2 INVENTOR. 0A v10 APo/vJo/v.

Patented Sept. 2, 1952 COMBUSTION APPARATUS USING COMPRESSED. AIR

David Aronson, Greensburg, Pa., assignor to. Elliott Company, Jeannette, 2a., a, corporation of. Pennsylvania Application March 14, 1950., SerialNm 149,588.

9 Claims. 1.

This-invention relates tocombustion apparatus, and more particularly to the delivery of compressed'airto a combustion chamber for creating turbulence therein'and cooling its walls.

In combustion apparatus utilizing compressed air, the combustion chamber walls are provided with openings through which air is admitted. In most cases this air enters with two velocity components; one radial and one parallel with the axis of the chamber. The axial component is presentbecause-the chamber generally has inner and-outerwallswhich forman annular passage through which air can flow from one end of the chamber to the other. The outer wall may or may; not be a pressure wall. The flow of air through the annular-passage cools the innerwall by forced convective heat't'ransfer between the metal and the air. The higher the air velocity in this passage the more effective is the cooling action. The'radial componentof the air entering the combustion zone produces a high degree of turbulencewhich aids the combustion process by mixing the fuel and air. At a given pressure dropacross the combustion chamber walls, the magnitude of the radial component decreases 'as the axial component increases, Therefore, in

order to obtain both adequate cooling of the chamber walls and effective mixing of. fuel and air. itis necessary to have a large pressure drop.

v It'is among the objects ofthis invention to provide. combustion, apparatus of the type discussed above in. which eiiicient combustion is produced at lower. air pressure losses than heretofore, in

which. the full pressure drop. of the, compressed ,airis availableior producing turbulence in the combustion zone. as well as for cooling of the chamber. walls, inwhich the twotypes of air. flow have pressure drops which are equal butnot additive, and in which the inner combustion chamber Wall. may be supported by tubular members through. which air is deliveredto the combustion zone.

In accordance Withthis invention, the combusti'on apparatus includes a combustion chamber formed from spaced inner and outer walls. The inner wall is'providedwitha plurality of circumferentially spaced openings, to which are connected tubular members that extend out beyond the space, between the. two walls. A burner is disposed'at. one endottheinnerwall. Air under pressureis .directedto the outerends of the tubular-members and. tothe, spacebetweenthe burner .endof: the inner wall and"the-surroundingouter wall. Thisair imay-be delivered throughseparate conduits.v or: to; acasingpsurrounding rtheecombus- 2 tion chamber walls. The full pressure drop of the. airis thus available for turbulent. mixing within/the combustion .zone, and at the same time the full pressure drop also is available for. cooling the combustion chamber walls. Preferably, the tubular members extend radially out through the outer wall of the combustion chamber and are slid'ably mounted in oneof thewalls so as to*-support theinner walland permit it'to expandlfreely. Also, it-ispreferred to formed the inner wallirom telescoping rings, that are spaced apart radially to permit some of the air-to flow axially between them.

The preferred embodiment of the inventiolris illustrated in the; accompanying drawings, in which Fig. 1 is a side view of the combustion apparatus, shown partly in; longitudinalselction; Fig. 2 is an enlarged longitudinal section-of one of the tubular members; Fig. 3: is a view of the burner end of the combustionchambem' and-:Eig. a is a cross section taken on the line IV--IV of Fig Referring to the drawings, the outer wall oftthe combustion chamber is formed from a longcylindrical shell I, the inner end ofwhich may be tapered to reduce its diameter. Bolted to the inner end of this shell is a bolting ring 2 which is connected by several radial spokes 3 to an inner bolting ring 4 that is concentric with theouter one. The inner ringis bolted to a flange 6' encircling one end of a sleeve I, through which a burner 8 mayproject into the combustion chamber. The flange t is clamped between the inner bolting ring 4 and a flange 9 on the reduced 'end of an inner combustion chamber wall or liner H that isconcentrio with shell I and spaced from it'to provide an annular passage l2 between them extending'from end to end of the chamber. The liner can be a single member like the shell, but preferably is formed from a plurality of telescoping rings l3, l4, l5, It, l1, l8 and Hi. As just shown, the ring i3 at the inlet end of the liner is supported by the inner bolting ring 4. All of the. rings are disposed on. the same axis and are spacedapart radially, with .the largestring at the outlet end of the chamber. The radial spacing provides annular spaces between the difierent .ring s so. that forwardly directed. air can. flow combustion chamber walls.

'Each of the linerrings, with theexception-of the; one (l.3').,at the inner end of the chamber,

available for cooling the chamber walls.

is shown provided with a plurality of circumferentially spaced openings 2|. Four equally spaced openings in each ring have been found to he satisfactory, although more can be used if desired. These openings are so spaced lengthwise of each ring as to fall between the ends of the two adjoining rings. It is a feature of this invention that each of these ring openings is connected by a tubular member to the space outside of the shell I so that none of the air flowing through passage [2 between the two walls of the combustion chamber will be diverted radially through openings 2|.

Accordingly, each of the tubular members just mentioned includes a sleeve 22 welded to the outside of each liner ring around each of its radial openings. The sleeves are disposed radially of the rings and extend only part way across the space between the rings and the encircling ,shell. Each sleeve is slidably mounted on the inner end portion of a rigid metal tube 23 that extends out through an opening 24 (Fig. 2) in the shell. The outer end portion of the tube preferably extends through an threaded collar 26 that has a head engaging the inner surface of the shell. A nut 21 is threaded on the outer end of this collar and is tightened against the outer surface of the shell to clamp the collar in place. The opening in the shell, through which the collar extends, is larger than 'the body of the collar so that before the nut is tightened the collar can be adjusted laterally to the proper position in axial alignment with the adjacent sleeve. The tube 23 that extends through the collar can be held in place by a cotter pin 28 extending through aligned radial openings in the outer end of the tube and the portion of the collar projecting beyond nut 21.

It will be seen that by this arrangement each liner ring can be independently supported inside the shell with its axis coinciding with the axis of the shell. Also, when the liner becomes hot, each ring is free to expand independently of the other rings and of the shell, because the sleeves '22"can slide outward on the supporting tubes 23. Consequently, the liner rings, which are at the highest temperature, do not act as structural members. That should prolong their useful life.

' Because the tubular members, consisting of the telescoping tubes 23 and sleeves 22, extend out beyond shell l, none of the compressed air that enters passage l2 between the combustion chamber walls can enter the openings 2| in the sides of the liner rings. As a result, the full pressure drop of the air in passage I2 is The air for turbulent mixing is introduced through the tubular members, by which the liner rings are supported. This air enters the combustion zone with virtually zero axial component, so its full I pressure drop is available for mixing. Thus, the two functions of the air in the combustion chamber are separated and it is not necessary to have a pressure drop that is the sum of the pressure drop required for turbulent mixing and the pressure drop required for satisfactory wall cooling. It is only necessary to have a pressure drop that .is adequate for the function requiring the greater pressure drop, because that will be sufficient for the other, too.

,It is preferred, although not essential, to

supply the high pressure air to the combustion chamber from a casing 30 of any suitable construction surrounding the chamber. The casing may completely surround the combustion chamexternally ber, except for an outlet 3| which is concentric with the outlet of the chamber. The inner end of the combustion chamber is supported in the casing by a short, heavy tube 32 that is telescoped into sleeve 7, but spaced radially from it by circumferentially spaced bosses 33 so that air can enter 'the sleeve. The outer end of the tube extends through the end wall of the casing and is rigidly mounted in a ring 34 that is bolted to the end wall. Bolted to the outer surface of the ring is a plate 36 provided with a central opening, to which a fuel pipe 31 is connected. This plate also supports the outer end of the burner 8, the inner end being supported by a transverse wall 38 in the tube 32. The outer end of the shell I may be supported by a transverse wall 39, through which the shell projects. This wall prevents air from flowing from the casing inlet 40 directly to its outlet without entering the combustion chamber.

The air is delivered to the casing inlet'under pressure from a blower or compressor (not shown). Some of the air will flow past the bolting rings 2 and 4 and. into passage [2 between the two walls of the combustion chamber. This air will flow lengthwise of the chamber and out of its opposite end. Another portion of the air in the casing will enter the outer ends of tubes 23 and flow radially into the combustion zone to create turbulence. The full pressure drop of the air thus is available for both functions of the air. This invention removes the radial velocity component from the axially flowing air, and also removes the axial velocity component from the radially flowing air. The two functions of the air in the combustion chamber therefore are separated and pressure losses are greatly reduced. 7

It will be seen that by using a larger diameter casing 30, several combustion chambers can be mounted side by side in the same chamber when that is desirable.

The combustion apparatus disclosed herein is intended primarily for use as part of a gas turbine plant. However, it can be used for such apparatus as drying ovens, high temperature processing and wherever an atmosphere at elevated temperatures (such as in the range from 300 F. to 2000 F.) is required. This apparatus is not intended for general furnace application where it is desirable to operate with the least possible amount of excess air. The tubes 23 not only supply most of the air required for combustion, but they also form supports for the several liner rings. Where the particular operating conditions under which this apparatus is used do not require the full air flow, some of the tubes can be plugged, but they will still serve as supports.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specificially illustrated and described.

I claim:

1. Combustion apparatus comprising inner and outer combustion chamber walls of approximately the same length having a space between them, said space extending substantially the length of the combustion chamber, the inner wall being end ofsaid inner-wallvand the surrouridin tei' wan, "the casing being provided'with v for-air "under-pressure, whereby j so of the air in'the casing will enter said space and some will enter the outer ends of said tubular members, said space having an outlet at the opposite end of said innerwall.

6. Combustion apparatus comprising a longitudinally tapered" inner combustion chamber wall *Inrmed', from radially spaced telescoping :rings, a burner disposed at the smaller end. of sairlin rings ner wall, anrouter combustionchamber wall surprovided with a plurality of circumferentially rounding the inner wall andspaced therefrom, spaced openings, radially disposed rigid tubular means near the opposite ends of the inner; wall members connected to said inner wall at said {for supporting the outer-wall, said rings being openings and extending through said outer wall providedwith'circumferentially spacedopenings, for supporting the rings from the outer wall, a tubular members having their inner ends conburner disposed at the smaller end of the tapered nected to the rings at said openings in the space inner wall, and means for directing airunder between the two walls and having their outer pressure to the outer ends of said tubular mem ends located outside of the outer wall, said space bers and to the space between the smaller end having an inlet at the smaller end of the inner of the imier wall and the surrounding outer wall and an outlet at the opposite end, and ll, means for directing air under pressure to the 3. Combustion apparatus comprising spaced outer ends of said tubular members and to the inner and outer combustion chamber walls, the space between the smaller end of the inner wall the outside ofsaid outer wall, arena: end 'ofthe inner' wal rectingair imder pressure to said tubular members and t "the burner end'oftheinn'e rounding outerwall.

inner wall being provided with a plurality of cirand the surrounding outer wall.

cumferentially spaced openings, radially disposed '7. Combustion apparatus comprising a longirigid tubular members connected to said inner tudinally tapered inner combustion chamber wall wall at said openings and extending through said formed 'from radially-spaced telescoping rings, outer wall for supporting the inner wall from a burner disposed at the smaller end of said the outer one, said tubular members having slidinner wall, an outer combustion chamber wall ing connection with one of said walls to permit surrounding the inner wall and spaced theresubstantially unrestrained thermal expansion of from, said rings being provided with circumthe inner wall, a, burner disposed at one end of ferentially spaced openings, radially disposed the inner wall, and means for directing air under rigid tubular members connected to the rings pressure to the outer ends of said tubular memat said openings and extending through said bers and to the space between the burner end outer wall for supporting the rings from the outer of the inner wall and the surrounding outer wall, said tubular members having sliding cona11, nection with one of said walls to permit sub- 4. Combustion apparatus comprising spaced 40 stantially unrestrained thermal expansion of the inner and outer combustion chamber walls, the rings, and means for directing air under presinner wall being provided with a plurality of cirsure to the outer ends of said tubular members cumferentially spaced openings, tubular memand to the space between the smaller end of the here in the space between the two walls, the ininner wall and the surrounding outer wall.

ner ends of said members being connected to 8. Combustion apparatus comprising radially said inner wall at said openings and the outer spaced inner and outer combustion chamber walls ends of said tubular members extending out of provided with circumferentially spaced aligned said space, a burner disposed at one end of the pairs of openings, radially disposed sleeves rigidinner wall, and a casing enclosing said walls and I 1y connected to said inner wall at the openings forming an air pressure chamber receiving the; therein, rigid tubes rigidly mounted in the openouter ends of said tubular members and com; ings in the outer wall and slidably mounted in municating with the space between the burner the adjoining sleeves to support the inner wall end of said inner wall and the surrounding outer and permit it to expand, a burner disposed at wall, the casing being provided with an inlet for one end of the inner wall, and means for diair under pressure, whereby some of the air in recting air under pressure to the outer ends of the casing will enter said last-mentioned space said tubular members and to the space between and some will enter the outer ends of said tubular the burner end of the inner wall and the surmembers, the space between said walls being prorounding outer wall.

vided with an outlet located between their ends 9. Combustion apparatus comprising a longiopposite to said burner end. tudinally tapered inner combustion chamber wall 5. Combustion apparatus comprising spaced formed from radially-spaced telescoping rings,

inner and outer combustion chamber walls, the a burner disposed at the smaller end of said inner wall being provided with a plurality of cirinner wall, an outer combustion chamber wall cumferentially spaced openings, radially disposed surrounding the inner wall and spaced therefrom, rigid tubular members connected to said inner 6 said rings being provided with circumferentially wall at said openings and extending through said spaced openings, the outer wall being provided outer wall for supporting the inner wall from the with openings aligned with said ring openings, outer one, said tubular members having sliding radially disposed sleeves rigidly connected to connection with one of said walls to permit subsaid rings at the openings therein, rigid tubes stantially unrestrained thermal expansion of the 7 rigidly mounted in said outer wall openings and inner wall, a burner disposed at one end of the slidably mounted in the adjoining sleeves to inner wall, and a casing enclosing said walls and support the rings and permit them to expand, forming an air pressure chamber receiving the and a casing enclosing said walls and forming outer ends of said tubular members and coman air pressure chamber receiving the outer ends un ca W t the pa between the bu of said tubes and communicating with the space 7 between the burner end of said inner wall and the surrounding outer wall, the casing being pro vided with an inlet for airunder pressure, whereby some of the air in the casing will enter said space and some will enter the outer ends of said tubes.

DAVID ARONSON.

1,857,556 Lasley May 10, 1932 1 1,918,397 Jezler July 18, 1933 Number Number 8 Name Date Seippel Dec. 30, 1941 Goddard Mar. 12, 1946 Lubbock. et a1 Apr. 16, 1946 Peterson et al. July 27, 1948 Parrish Oct. 4, 1949 Bonvillian et al. Mar. 21, 1950 McMahan June 6, 1950 FOREIGN PATENTS 7 Country Date Great Britain Oct. 19, 1948 

